The present invention generally relates to residential furnace diagnostic systems. More particularly, the invention pertains to a method for measuring, storing, reporting and analyzing furnace diagnostic information as well as the electronic circuitry and software capable of implementing such method.
The complexity of modern heating systems has complicated the diagnosis and repair of faults from which such systems may suffer. Misdiagnosis and the replacement of the wrong components is both expensive and time consuming and can pose a substantial nuisance to all involved. On the one hand, the homeowner is subjected to a continued malfunction of the heating system and must accommodate repetitive service calls. On the other hand, the service provider must expend time and labor to repeatedly send personnel into the field to address the problem while the furnace manufacturer may be called upon to supply replacements for components that are in fact fault free and fully operational.
Some progress has previously been made to facilitate a more comprehensive analytical approach to the operation of furnace systems and to thereby allow problems to be more quickly and efficiently diagnosed and the underlying faults to be correctly identified. This has included both the modification of furnace configurations to actively accommodate the monitoring of various functions as well as the development of external analytical tools that are capable of probing the operation of existing furnace systems. However, none of the heretofore known approaches have provided an adequately comprehensive system that exploits all of the tools that are currently available to thereby allow problems to be identified as quickly and accurately as possible.
In certain previously known systems, monitoring and diagnostic systems have been integrated within a furnace to thereby provide for a data collection and memory capability. Operating data, including malfunctions are logged and can be accessed by a service technician using a portable, hardwired data reading unit.
Other systems have been devised wherein an integrated electronic furnace control arrangement incorporates a self test feature which shuts down the furnace in the event of any one of a number of possible sensed faults. This system tests furnace sensors for false indications both while the sensor should be detecting a particular burner parameter as well as when the sensor should not be sensing that parameter and in the event of a discrepancy, performs a safety interrupt and lockout command to shut down the furnace. Additional features that may be present include a multipurpose display for selectively showing component indicative failure codes, temperature setback schedules, time of day, and day of the week.
Systems have been described that incorporate a direct ignition gas burner control system using a microcomputer and related circuitry for controlling the energizing of the ignitor and valves and for numerous checks on the integrity of the system components. Such systems may include an ignition control processor which transmits coded data signals to a portable display module via a hard-wire conduit connection. The portable display module contains a processor to process the signals received from the ignition control processor and to control a display device to display selected operating modes and last known failure conditions in human-readable form. Residence appliance management and communication systems are also known that include an interface module installed on each home appliance. In the case of the furnace, the interface module interfaces with the furnace microprocessor and reports furnace component status and failures to a central controller.
However, while such systems aid in the diagnosis of certain faults a furnace may suffer from, none of the systems that have previously been described enable a technician to enjoy the full benefit of computerized analysis of real time as well as historical data. A system is needed wherein all such capabilities can simultaneously be brought to bear on a particular problem to allow an underlying fault to be quickly and accurately identified. Such system must not only be efficient in its operation but must be easy to transport and use in the field.
The present invention provides a novel method and apparatus for acquiring, reporting and analyzing diagnostic information for furnaces to facilitate troubleshooting and repair. The invention is couched in the recognition that a number of different factors can contribute to a misdiagnosis, including a technician""s inability to quickly and easily test a system""s various functions to thereby identify faults in real time. Additionally, in the event a particular failure mode is intermittent, an inability to recall the circumstances relating to previous malfunctions can prevent positive identification of the problem. A technician""s unfamiliarity with the failure and repair history of the particular unit subject to the malfunction may additionally inhibit a quick and accurate diagnosis. Finally, the inability to quickly and properly analyze a particular set of symptoms in the context of the past history of the individual heating system as well as the whole population of such systems may thwart efforts to accurately diagnose and hence quickly and efficiently remedy a particular problem.
The present invention addresses each of the above-described sources of or reasons for misdiagnosis. Moreover, the invention enables a technician to quickly and easily generate and retrieve all relevant data from the furnace and avails the analytical power of remote diagnostic facilities to analyze the data. As such, the system of the present invention includes various sensors that are integrated throughout a furnace that monitor its various functions, is capable of storing data generated by such sensors to create a fault history and allows a technician to access such data via a remote, handheld device. The handheld device additionally allows the technician to control the system""s various functions and thereby generate real time data relevant to its operation. The handheld device serves to analyze the data to diagnose the underlying problem. Finally, the system allows data to be transferred to a remote centralized computing facility for further processing. Such centralized facility is capable of storing a large body of data pertaining to the operation and fault history of the entire population of individual furnace systems in the field. The ability to draw from such database provides further assistance for the technician to enable him to more quickly and accurately correlate a particular set real time and/or historical data with an underlying fault.
Thus, briefly and in general terms, in one aspect the present invention is directed to a plurality of sensors in combination with electronic circuitry for measuring various furnace parameters.
In another aspect, a software system is provided to reside on a microcontroller and interface with the electronic circuitry to access the acquired diagnostic information, and to further interface with a portable handheld device to provide the information to a system user.
In another aspect, electronic circuitry and software is provided that is capable of storing data pertaining to the operation of the furnace for future access thereto.
In a further aspect, the invention consists of a microcontroller based furnace controller for a residential furnace with various sensors and a wireless hand held display device (such as a PalmOS(trademark) device). Both real time data as well as stored historical data is accessible by the handheld device for analysis. The invention thereby makes the integrates detailed diagnostic information and the latest in computing technology for the benefit of the service technician.
In another aspect, the invention imparts an ability to the technician to control the operation of the furnace via the handheld device to thereby generate real time data points without having to physically access the furnace control circuits.
Finally, in a further aspect, the invention provides for the storage of and access to performance/fault data from a population of similar furnace systems in a centralized database to further enhance the systems""s diagnostic ability.
These and other features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments, which taken in conjunction with the accompanying drawings, illustrate by way of example the principles of the invention.